Michael Milken, the man who virtually invented the market in high-yield junk bonds while working at Drexel Burnham Lambert Inc., pleaded not guilty today to a 98-count indictment that charged him with racketeering and securities fraud. Milken has always denied that he did anything wrong and has retained some of the nation's most expensive legal talent to defend him in what will very likely be a long and costly trial.

Lt. Col. Oliver L. North, who has shown a keen ability to parry questions at the Iran- contra hearings, found himself enjoying a bit of repartee Friday with one of his interrogators, Senate committee counsel Arthur L. Liman. The moment left both men laughing and relieved some of the tension produced by Liman's lengthy examination of the former White House aide.

Retired Air Force Maj. Gen. Richard V. Secord told the congressional Iran- contra investigating committees what he thinks about being regarded as a profiteer: not much. Senate committee counsel Arthur L. Liman asked Secord, in light of a "surplus" of $14 million generated by Iran sales, if there was a reason he didn't call it a "profit." This exchange followed: Secord: "Yes, because people have been calling me 'profiteer.' So I thought perhaps a change in terms might improve the accuracy."

Henry Kissinger, Frank Sinatra and Mary Tyler Moore are among celebrities who bought jewelry but did not pay sales taxes in a tax evasion scam run by an exclusive 5th Avenue store, law enforcement sources said Wednesday. The sources said none of the celebrities, who included billionaire Saudi Arabian arms dealer Adnan Khashoggi, would be charged in the tax evasion scam. A spokesman for the state attorney general's office said legal responsibility lies with the store.

The Scene: Sunday's premiere of Miramax's "Swingers" at the Vista Theater, the Egyptian / Art Deco gem in east Hollywood. A party followed at the nearby Derby club, which specializes in '40s big-band swing. It's where the Smashing Pumpkins generation meets the music of Bob Dole. * Plot Synopsis: The low-budget, indie comedy chronicles a brokenhearted actor's search for a girlfriend. He's taken by friends through L.A.'s "cocktail nation" retro bar scene.

Michael Milken's attorney today denied that the former junk bond king played any role in the 1986 manipulation of Wickes Co. stock, as a climactic hearing began in the government's four-year insider trading inquiry. Milken, 44, took copious notes and repeatedly shook his head or rolled his eyes as Assistant U.S. Atty. John K. Carroll laid out the first of three alleged crimes against Milken being aired at the pre-sentencing hearing. The unusual hearing before U.S.

A federal judge today ordered a special mini-trial in the government's case against Michael Milken to give her a better understanding of the junk bond king before he is sentenced. At the hearing, expected to last about two weeks, prosecutors say their witnesses may include stock speculator Ivan Boesky, Boesky assistant Michael Davidoff and Drexel trader Carey Maultash. Milken, 44, the former head of the high-yield junk bond division of Drexel Burnham Lambert Inc.

Michael R. Milken, the investment star who has been caught up in the government's continuing investigation into illegal Wall Street trading practices, has been meeting with some of the nation's leading white-collar criminal lawyers.

Walt Disney Co.'s former chief financial officer testified Thursday that raider Saul P. Steinberg might have made "at least" a $1.2-billion profit if he had taken control of the company at the price he proposed in 1984. The assessment was based on management data on the "breakup" value of Disney's assets at the time. As a witness in a so-called greenmail trial, retired Disney executive Michael Bagnall said he believed Steinberg "was trying to steal the company" when he offered $62.

"Why does Ghorbanifar hate Hakim--and vice versa?" Arthur L. Liman, chief counsel of the Senate special committee investigating the Iran- contra scandal, was packing his briefcase after the hearings Friday when this question was shouted at him. "I don't usually answer those questions," Liman said. "But this one, I will." The animosity between two of the major figures in the Iran-contra scandal, Manucher Ghorbanifar and Albert A. Hakim, is attributable to competitiveness, Liman suggested.